Category Archives: Science-related issues

Society shrinks our brains?!?

(Originally from http://bigthink.com/ideafeed/human-brain-size-is-shrinking-thank-domesticity)

Human Brain Size Is Shrinking. Thank Domesticity.

Over a year ago by ORION JONES

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What’s the Latest?

Using fossil records to measure cranial capacity through the millennia, researchers have found that as we become increasingly domesticated as a species, the size of our brain continues to shrink. Bruce Hood, psychologist at the University of Bristol, UK, says shrinkage is best explained by changes in society: “We have been self-domesticating through the invention of culture and practices that ensure that we can live together.” Hood notes that as humans have domesticated other species, from cows to dogs, their cranial capacity has also shrunk as they learn to enlist the help of their human masters rather than invent their own solutions.

What’s the Big Idea?

Where our brains have lost capacity, our ability to share knowledge across society has blossomed. This is what, according to Hood, has made our species so successful. “Knowledge can be broadly distributed, disparate areas of expertise collaboratively coordinated, and technology can develop over many generations.” Our dependency on shared knowledge at the community level, however, is also ripe for abuse. “The importance we place on allegiances, for example, is all too easily manipulated by unscrupulous leaders, and deplorable actions are too readily committed through what Hood calls ‘diffusion of accountability’.”

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Stand up to bigotry, even from your own!

Not too long ago (18th August to be exact) something out of the ordinary happened. On my way home on the bus a ‘black’ lady, I’d guess in her early 20s, was getting harrassed by a ‘black’ guy, maybe early-mid 30s, who kept walking back and forth up the bus. Let’s call him Dumbshit. Continue reading Stand up to bigotry, even from your own!

The purpose of (male) circumcision

(Disclaimer: this post won’t go into much depth on the origins of circumcision. That’s too lengthy a discussion and can be read about on Wiki. My focus is on its purpose in Judaism, which by proxy explains its purpose in Christianity and Islam)

Continue reading The purpose of (male) circumcision

Fair skin doesn’t do shit for vit D levels

(Reposted from https://www.ucsf.edu/news/2014/06/115741/human-evolution-changes-skin’s-barrier-set-northern-europeans-apart)

In Human Evolution, Changes in Skin’s Barrier Set Northern Europeans Apart

UCSF Study Questions Role of Skin Pigment in Enabling Survival at Higher Latitudes

 

A microscopic image of skin cells.

 

The popular idea that Northern Europeans developed light skin to absorb more UV light so they could make more vitamin D – vital for healthy bones and immune function – is questioned by UC San Francisco researchers in a new study published online in the journal Evolutionary Biology.

Ramping up the skin’s capacity to capture UV light to make vitamin D is indeed important, according to a team led by Peter Elias, MD, a UCSF professor of dermatology. However, Elias and colleagues concluded in their study that changes in the skin’s function as a barrier to the elements made a greater contribution than alterations in skin pigment in the ability of Northern Europeans to make vitamin D.

Elias’ team concluded that genetic mutations compromising the skin’s ability to serve as a barrier allowed fair-skinned Northern Europeans to populate latitudes where too little ultraviolet B (UVB) light for vitamin D production penetrates the atmosphere.

Among scientists studying human evolution, it has been almost universally assumed that the need to make more vitamin D at Northern latitudes drove genetic mutations that reduce production of the pigment melanin, the main determinant of skin tone, according to Elias.

“At the higher latitudes of Great Britain, Scandinavia and the Baltic States, as well as Northern Germany and France, very little UVB light reaches the Earth, and it’s the key wavelength required by the skin for vitamin D generation,” Elias said.

“While it seems logical that the loss of the pigment melanin would serve as a compensatory mechanism, allowing for more irradiation of the skin surface and therefore more vitamin D production, this hypothesis is flawed for many reasons,” he continued. “For example, recent studies show that dark-skinned humans make vitamin D after sun exposure as efficiently as lightly-pigmented humans, and osteoporosis – which can be a sign of vitamin D deficiency – is less common, rather than more common, in darkly-pigmented humans.”

Furthermore, evidence for a south to north gradient in the prevalence of melanin mutations is weaker than for this alternative explanation explored by Elias and colleagues.

In earlier research, Elias began studying the role of skin as a barrier to water loss. He recently has focused on a specific skin-barrier protein called filaggrin, which is broken down into a molecule called urocanic acid – the most potent absorber of UVB light in the skin, according to Elias. “It’s certainly more important than melanin in lightly-pigmented skin,” he said.

In their new study, the researchers identified a strikingly higher prevalence of inborn mutations in the filaggrin gene among Northern European populations. Up to 10 percent of normal individuals carried mutations in the filaggrin gene in these northern nations, in contrast to much lower mutation rates in southern European, Asian and African populations.

Moreover, higher filaggrin mutation rates, which result in a loss of urocanic acid, correlated with higher vitamin D levels in the blood. Latitude-dependent variations in melanin genes are not similarly associated with vitamin D levels, according to Elias. This evidence suggests that changes in the skin barrier played a role in Northern European’s evolutionary adaptation to Northern latitudes, the study concluded.

Yet, there was an evolutionary tradeoff for these barrier-weakening filaggrin mutations, Elias said. Mutation bearers have a tendency for very dry skin, and are vulnerable to atopic dermatitis, asthma and food allergies. But these diseases have appeared only recently, and did not become a problem until humans began to live in densely populated urban environments, Elias said.

The Elias lab has shown that pigmented skin provides a better skin barrier, which he says was critically important for protection against dehydration and infections among ancestral humans living in sub-Saharan Africa. But the need for pigment to provide this extra protection waned as modern human populations migrated northward over the past 60,000 years or so, Elias said, while the need to absorb UVB light became greater, particularly for those humans who migrated to the far North behind retreating glaciers less than 10,000 years ago.

The data from the new study do not explain why Northern Europeans lost melanin. If the need to make more vitamin D did not drive pigment loss, what did? Elias speculates that, “Once human populations migrated northward, away from the tropical onslaught of UVB, pigment was gradually lost in service of metabolic conservation. The body will not waste precious energy and proteins to make proteins that it no longer needs.”

For the Evolutionary Biology study, labeled a “synthesis paper” by the journal, Elias and co-author Jacob P. Thyssen, MD, a professor at the University of Copenhagen, mapped the mutation data and measured the correlations with blood levels of vitamin D. Labs throughout the world identified the mutations. Daniel Bikle, MD, PhD, a UCSF professor of medicine, provided expertise on vitamin D metabolism.

The research was funded by the San Francisco Veterans Affairs Medical Center, the Department of Defense, the National Institutes of Health, and by a Lundbeck Foundation grant.

UCSF is the nation’s leading university exclusively focused on health. Now celebrating the 150th anniversary of its founding as a medical college, UCSF is dedicated to transforming health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy; a graduate division with world-renowned programs in the biological sciences, a preeminent biomedical research enterprise and two top-tier hospitals, UCSF Medical Center and UCSF Benioff Children’s Hospital San Francisco.

 

 

 

 

 

Why we should all be left-handed!

…Or at least ambidextrous.

This afternoon I just worked out The Answer™ to why most world cultures revere the right hand so much!

According to modern neuroscience, the 2 hemispheres of the brain have specialised functions. The left side is associated with reason, order, sense of reality & academic intelligence, and controls the right side of the body. The right hemisphere is associated with personal insight, sense of possibility, individuality & creativity, and controls the left side of the body. We also know about biofeedback, which basically says the rest of the body influences brain function just as much as the brain controls it. This means that using the left hand activates the brain’s right hemisphere and vice versa.

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¿Why is this important?

Say you’re a ruler of a nation (legitimacy irrelevant) and you want people to obey your laws. Problem: these people are already happy with their own principles & traditions, and their religions are multi-faceted, experiential and prioritise different things to you, so why the bloodclaat should they wanna obey you? And since they outnumber you, how could you make them obey you?

Answer: change their behaviour so they automatically conform! If you’ve paid enough attention to people’s behaviour, you’ll have noticed that certain actions develop/ activate certain ways of being (biofeedback). One of those might be, oh I don’t know, using the left hand activates the same side of the brain that governs individuality! And since right-hand use activates the other side of the brain – the side that acquiesces to logic and order (i.e. your laws) – why not institute a tradition that reveres right-handedness?

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Use the right hand for everything: eating, drinking, greeting, lifting, sawing wood, ploughing fields, reading holy books, all that jazz! And just for good measure, reserve the left hand for unpleasant activities like wiping your ass (bare-handed in the case of early Muslims at least)!

Of course that won’t be the whole solution. Suppressing certain forms of sexuality and worship would certainly go into the mix, but controlling people’s handedness could play a subtle yet ridiculously powerful role. And you might want to keep that going by, let’s say, encoding right-hand reverence in religion and culture – and “righting” those who don’t conform.

Maybe even have them earn less money, for reasons beyond your control of course.

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Then hundreds or thousands of years pass, and for the most part people have been successfully programmed into activating their orderly uncreative left hemisphere. You’re one of them, but you’re disillusioned now. You want to make a physical change in your life because it feels shit. You read all these self-help books and tapes and the rest that talk about changing your spiritual state first.

What if, at least for some, that doesn’t work?

What if action & behaviour needs to be changed before any spiritual change can happen?

What kind of change could be made? And what kind of feedback would that give your brain…?